A076561 a(1)=2; a(n>1)= greatest prime divisor of {a(n-1) + n}.

2, 2, 5, 3, 2, 2, 3, 11, 5, 5, 2, 7, 5, 19, 17, 11, 7, 5, 3, 23, 11, 11, 17, 41, 11, 37, 2, 5, 17, 47, 13, 5, 19, 53, 11, 47, 7, 5, 11, 17, 29, 71, 19, 7, 13, 59, 53, 101, 5, 11, 31, 83, 17, 71, 7, 7, 2, 5, 2, 31, 23, 17, 5, 23, 11, 11, 13, 3, 3, 73, 3, 5, 13, 29, 13, 89, 83, 23, 17

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Mathematica

nxt[{n_, a_}]:={n+1, Max[FactorInteger[a+n+1][[All, 1]]]}; NestList[nxt, {1, 2}, 80][[All, 2]] (* Harvey P. Dale, Jan 06 2023 *)

Prog

(PARI) lista(nn) = {v = vector(nn); v[1] = 2; for (n=2, nn, f = factor(v[n-1]+n); v[n] = f[#f~, 1]; ); v; } \\ Michel Marcus, Aug 08 2014

Crossrefs

Cf. A076560 (a(1)=1).

Sequence in context: A097611 A135376 A132850 * A132851 A361119 A293833

Adjacent sequences: A076558 A076559 A076560 * A076562 A076563 A076564

Keyword

easy,nonn

Author

Zak Seidov, Oct 19 2002

Extensions

Definition clarified by Harvey P. Dale, Jan 06 2023

Status

approved